TO control the speed of DC Motor Simple Project

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TO control the speed of DC Motor Simple Project

  1. 1. PRESENTED BY: MUQADSA IFTIKHAR CLASS NO. 03 REG. NO (09ABELT0290) ZUNAIB ALI CLASS NO. 09 REG. NO (09ABELT0296) Supervised BY: ENGR. SANIA SAEED
  2. 2. ABSTRACT• The purpose of a motor speed control is to take a signal representing the demanded speed and drive the motor at that speed.
  3. 3. INTRODUCTION The speed of dc motor is directly proportional to the supply voltage, if we reduce the supply voltage from 12V to 6V, the motor will run at half the speed. SCR “phase-angle controlled” drive -By changing the firing angle, variable DC output voltage can be obtained. Here we are using microcontroller applications. For this we are using AT89C51 IC and by using this we are setting the speed of motor.
  4. 4. MAIN COMPONENTS1. 220 V , 50Hz AC Supply2. Step Down Transformer3. DC motor4. Micro controller5. Thyristor (SCR)6. NPN Transistor7. Crystal Oscillator (11.0592MHz)8. 5V DC Supply
  5. 5. DC MOTOR The DC motor is electric motor that runs on direct current electrically. DC motor works based on the LORENTZ FORCE. In DC motor voltage is proportional to speedADVANTAGES Low initial cost High reliability Simple control of motor speed
  6. 6. Block Diagram
  7. 7. Zero Crossing Detector 0 2 t 0 9ms 18ms t Sinusoidal input t 0 2 3 Zero Detector Output
  8. 8. Micro- Controller AT89c51 A smaller computer On-chip RAM, ROM, I/O ports. CPU RAM ROM Serial I/O Timer COM Port Port A single chip Microcontroller
  9. 9. CIRCUIT DIAGRAM
  10. 10. AT89C51 Programming: #include <reg51.h> case 1: unsigned char x, y; x=0x66; sbit driv = P2^2; y=0xFC; void main() break; { P1=255; case 2: P2=0x00; x=0xCC; IE=0x81; y=0xF8; break; while(1) case 3: { switch (P1) x=0x33; { y=0xF5; case 0: break; x=0xFF; case 4: y=0xFF; x=0x99; break; y=0xF1; break;
  11. 11. Continue… case 5: case 9: x=0xFF; x=0x99; y=0xED; y=0xDF; break; break; case 6: } x=0x66; } y=0xEA; } break; case 7: void External0(void) interrupt 0 x=0xCC; y=0xE6; { break; driv =0; case 8: TMOD=0x10; x=0x32; TL1=x; y=0xE3; TH1=y; TR1=1; break;
  12. 12. Continue… while(TF1==0); TR1=0; TF1=0; driv=1; TMOD=0x01; TL0=0xCC; TH0=0xF8; TR0=1; while(TF0==0); TR0=0; TF0=0; driv=0; }
  13. 13. Explanation: Input 220V, 50Hz is step down to 30V, 50Hz. This 30V, 50Hz is applied to Controlled HWR with DC motor as load. For the gating circuitry the same input 30V, 50Hz is applied to zero crossing detector to generate an external interrupt. Logic states are used to provide firing angle α. When the external interrupt occurs micro-controller generates pulse according to provided α.
  14. 14. Outputs for Different Firing Angle:For α = 0 Voltage Across Motor HWR Rectifier Output
  15. 15. Continue…For α = 7ms Voltage Across Motor HWR Rectifier Output
  16. 16. Continue…For α = 3ms Voltage Across Motor HWR Rectifier Output
  17. 17. Software Simulation:
  18. 18. Extension of Our Project
  19. 19. Applications ROBOTIC CONTROLS. SWING MACHINES. ELECTRONIC BIKES. WINDING MACHINES. DC OPERATED DRILL MACHINES. MOBILE AIR CONDITION FANS. TOYS. ELCTRONIC DOOR CONTROLLERS. ELECTRONIC CHAIRS (beauty parlor etc.)
  20. 20. CONCLUSION We have achieved the required speed and thyristor is a very good device for obtaining the variable DC there by controlling the motor speed. This circuit is just a basic circuit for understanding DC motor speed control. In case of HWR we got zero voltage in negative half cycle that’s why has power efficiency.
  21. 21. Any query
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